ISLAMABAD — Pakistan hit out at the United States on Friday over what it said was an incursion into its airspace by a NATO jet that attacked a military post.

The foreign ministry said in a statement the aircraft had attacked the the Ziarat post, 2.5 kilometres (1.5 miles) from the border with Afghanistan in Mohmand tribal region.

“Pakistanâ€™s serious concern over the air incursion has been conveyed to the US embassy in Islamabad,” spokeswoman Tehmina Janjua said.

She said Islamabad had launched an inquiry, adding that the US and NATO were also investigating the incident.

The foreign ministry has not said when the incursion happened or if anyone was wounded or killed.

But a security official said: “At least two foreign fighter jets violated Pakistan’s airspace on Friday and dropped six bombs near the post.”

An intelligence official in the area and a local administration official confirmed the incident and said there were no reports of any deaths.

The Pakistani military often accuses NATO’s ISAF force of violating Pakistan’s airspace in the hunt for Taliban who launch attacks in Afghanistan before fleeing back across the border.

Pakistan temporarily shut the main land route for NATO supplies into Afghanistan last September after officials accused NATO of killing Pakistani troops in another cross-border attack.

The northwest region is being targeted by a record number of US drone strikes, the number of which has doubled in the last year, with more than 100 strikes killing over 670 people, according to an AFP tally.

Fifteen US drone strikes have now been reported in Pakistan’s tribal belt since US commandos found and killed bin Laden in a unilateral airborne raid on the Pakistani garrison city of Abbottabad on May 2.

Relations between Pakistan and the US, wary at the best of times, deteriorated sharply over the raid, which humiliated the Pakistani military and invited allegations of incompetence and complicity.